This invention relates to rotary mechanisms such as rotary engines, pumps, expanders, compressors, or the like. More specifically, the invention relates to improved cooling of the rotor employed in such mechanisms.
Cooling the periphery of a rotor in a rotary mechanism by means of oil within the rotor is difficult because centrifugal force, during operation of the rotary mechanism having the rotor, causes the oil to move and remain radially outwardly within coolant cavities. Significant movement of the oil occurs only at its free surface within the coolant cavity, there being very little agitation of the coolant at radially outer peripheral portions of the cavity. As a result, the efficiency of heat transfer from the rotor to the coolant is low.
As a consequence, the surfaces of the rotor may run at a higher temperature than desired. Such high temperatures are not conducive to the maintenance of oil films necessary to ensure long life of seals carried by the rotor. Thus, the useful life of the mechanism is decreased and periodic maintenance is required at more frequent intervals than is desired.